The fxFlexOrder directive should be used on elements within a sorted fxLayout container and identifies the positional ordering of the element

<div fxLayout="row">
  <div fxFlexOrder="4">1. One</div>
  <div fxFlexOrder="2">2. Two</div>
  <div fxFlexOrder="3">3. Three</div>
  <div fxFlexOrder="1">4. Four</div>
</div>

fxFlexOrder takes a single integer as argument, and populates its host element with the following inline CSS styling